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// Copyright 2021 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef SRC_UTILS_ENUM_SET_H_
#define SRC_UTILS_ENUM_SET_H_
#include <cstdint>
#include <functional>
#include <type_traits>
namespace tint {
namespace utils {
/// EnumSet is a set of enum values.
/// @note As the EnumSet is backed by a single uint64_t value, it can only hold
/// enum values in the range [0 .. 63].
template <typename ENUM>
struct EnumSet {
public:
/// Enum is the enum type this EnumSet wraps
using Enum = ENUM;
/// Constructor. Initializes the EnumSet with zero.
constexpr EnumSet() = default;
/// Constructor. Initializes the EnumSet with the given values.
/// @param values the enumerator values to construct the set with
template <typename... VALUES>
explicit constexpr EnumSet(VALUES... values) : set(Union(values...)) {}
/// Adds e to this set
/// @param e the enum value
/// @return this set so calls can be chained
inline EnumSet& Add(Enum e) {
set |= Bit(e);
return *this;
}
/// Removes e from this set
/// @param e the enum value
/// @return this set so calls can be chained
inline EnumSet& Remove(Enum e) {
set &= ~Bit(e);
return *this;
}
/// @param e the enum value
/// @return true if the set contains `e`
inline bool Contains(Enum e) { return (set & Bit(e)) != 0; }
/// Equality operator
/// @param rhs the other EnumSet to compare this to
/// @return true if this EnumSet is equal to rhs
inline bool operator==(const EnumSet& rhs) const { return set == rhs.set; }
/// Inequality operator
/// @param rhs the other EnumSet to compare this to
/// @return true if this EnumSet is not equal to rhs
inline bool operator!=(const EnumSet& rhs) const { return set != rhs.set; }
/// @return the underlying value for the EnumSet
inline uint64_t Value() const { return set; }
private:
static constexpr uint64_t Bit(Enum value) {
return static_cast<uint64_t>(1) << static_cast<uint64_t>(value);
}
static constexpr uint64_t Union() { return 0; }
template <typename FIRST, typename... VALUES>
static constexpr uint64_t Union(FIRST first, VALUES... values) {
return Bit(first) | Union(values...);
}
uint64_t set = 0;
};
} // namespace utils
} // namespace tint
namespace std {
/// Custom std::hash specialization for tint::utils::EnumSet<T>
template <typename T>
class hash<tint::utils::EnumSet<T>> {
public:
/// @param e the EnumSet to create a hash for
/// @return the hash value
inline std::size_t operator()(const tint::utils::EnumSet<T>& e) const {
return std::hash<uint64_t>()(e.Value());
}
};
} // namespace std
#endif // SRC_UTILS_ENUM_SET_H_